A laugh turns into a snarl which gets stuck in the throat like a sob – or an arrow through the neck – in Bong Joon-ho's latest wild, wild ride, Parasite. On paper, that might not sound so very different from the experience of watching Bong's Snowpiercer, Memories Of Murder, The Host or Okja.
The Korean trickster god is above all known for his uncategorisable movie melees which tumble bloodily down the genre stairs hitting every step – comedy, horror, drama, social commentary, slasher, creature feature, murder mystery, manifesto for vegetarianism – on the way.
But while Parasite certainly cycles through more than half that list, the laugh is darker, the snarl more vicious and the sob more despairing than we've ever had from him before.
Bong is back and on brilliant form, but he is unmistakably, roaringly furious, and it registers because the target is so deserving, so enormous, so 2019: Parasite is a tick fat with the bitter blood of class rage.
It doesn't start off that way. Here we have a ramshackle but loving family driven to dubious extremes by poverty-stricken circumstance, and a rumpled patriarch (Song Kang-ho) who bursts amusingly with pride at even the most marginal of his kids' achievements. "Does Oxford have a course in forgery?" he asks admiringly, looking at the fake qualification his daughter Ki-Jung (Park So-dam) has comped together for her brother Ki-woo (Choi Woo-shik).
From their squalid "semi-basement" (a couple of dank rooms with a small strip of window against which drunken men are given to urinating) all four members of this family, including their ex-champion shot-putter mother Chung-sook (Chang Hyae-jin) struggle to find menial gig-economy jobs and an unlocked Wi-Fi signal. But then Ki-woo is offered the chance to replace a friend as the tutor for Da-hye (Jung Ziso), daughter of the wealthy Mr Park (Lee Sun-kyun).
Suddenly Ki-woo's days of folding pizza boxes for peanuts are behind him, and instead he gets to hang out with his lovestruck student and her naive mother Yeon-kyo (Cho Yo-Jeong) in the Parks' spacious architect-designed home.
When it turns out Da-hye's little brother Da-song (Jung Hyeon-jun) needs an art tutor, Ki-woo spots another opportunity and recommends his sister – in disguise as college acquaintance "Jessica." And so one more cuckoo settles into this luxuriously appointed nest.
Although this is the least loopy title from Bong in a while – there's no room for a cartoonishly broad, heavily dentured Tilda Swinton performance, for example – the first act bounces by with a devil-may-care gait as the scam expands, things start to look up for the family and while they've been roguish, no one has done anything so very unforgivable yet.
But even with proceedings at their jauntiest, the sincere classical score from Jung Jae-il and the restraint of the cinematography by Hong Kyung-po give Parasite a sheen of brushed-steel seriousness.
This is the most formally polished work we've seen from Bong: As opposed to the herky-jerk genre-hopping of The Host, here the story elides so seamlessly from one mood to the next that the joins are near-impossible to find, like those of the poured-concrete walls of the Parks' modernist dream home.
Production designer Lee Ha-jun's conception of the two contrasting residences, one a grotty subterranean hovel, the other a clean-lined work of liveable art on a gated suburban hillock fringed to perfect privacy with dense trees and shrubs, is a masterful example of evoking class difference through space and light. Those are commodities that apparently only the rich deserve.
It would have been easy for Bong and co-writer Han Jin-won to have made the privileged Parks overtly detestable, but time and again it is asserted just how nice they are. Mr and Mrs Park live a largely uncreased life, save for the slightest wrinkling of the nose when an unpleasant odour – perhaps the tang of poverty itself – assails them.
But for every gut-punch moment of blithe, enraging entitlement on their part, there's an equally horrible instance of selfishness or spite from their less moneyed counterparts: It takes a watchmaker's skill to keep the pendulum of our sympathies swinging back and forth between the grasping desperation of the poor and the idle hatefulness of the rich.
Tiny details, like the mention of a Taiwanese cake shop or the flickering of a hall lamp, all pay off in this most tightly plotted of Bong's films, building to a conclusion that is devastating and yet satisfying as an accretion of a thousand of those little moments.
So as plans go awry, quasi-Gothic revelations occur and things get pretty grisly, we've been so wholly worked into Bong's cleverly concealed sympathies that we might shock ourselves by feeling a sense of cathartic rightness at a moment of clearly wrong-headed violence.
The catharsis does not last long, though. As ferocious as this brilliant, caustic film is, with its flawless craft and humour – so dark it's like it, too, was bred in a basement and never saw the sun – it also rumbles constantly with a bleak growl at just how little all this high drama can actually ever matter, an impression reinforced by Hong's dispassionate, almost sardonically pristine camera.
Even this grand battle royale between the haves and have-nots will only ever be a squabble at the feet of an indifferent god, or worse still, a sideshow indulged to distract its participants from the real enemy, which is a system that creates and nourishes such divides in the first place.
This is the sad little truth evoked in the film's unexpectedly moving final moments: Eat the rich, by all means, fill your bellies, but pretty soon you'll be hungry again, and you will still be poor. – Reuters/Jessica Kiang
Director: Bong Joon-ho
Cast: Song Kang-ho, Lee Sun-kyun,Choi Woo-sik, Park So-dam